The present invention relates to an adjustable valve and, more particularly, to a non-invasively adjustable valve for shunting excess cerebrospinal fluid (CSF) from a ventricle in the brain to another location in the patient's body when the pressure differential between the CSF and the other body fluid reaches a predetermined magnitude, and to an adjustment mechanism therefor.
Hydrocephalus is a condition in which the brain is unable to relieve itself of CSF which collects in the ventricles of the brain. Such CSF, thereby, becomes excessive and results in abnormal ventricular size causing a number of adverse physiological effects including compression of the brain tissue and impairment of the blood flow in the brain tissue and of the brain's normal metabolism.
A variety of CSF regulator valves have been employed in the past for controlling CSF pressure. Such valves include various forms of check valves, servo valves or combinations thereof. One such valve is disclosed in application Ser. No. 467,326, filed Feb. 17, 1983, of which this application is a continuation-in-part.
In the last mentioned valve, a diaphragm containing a valve seat is positioned in the valve casing and both sides of the diaphragm are exposed to the CSF fluid. A ball closure valve is mounted by a threaded screw member in the casing so as to engage the valve seat. The force by which the ball closure engages the valve seat, and thereby, the pressure differential at which the CSF fluid will drain may be adjusted by threading the screw member in or out.
The present invention is directed to an adjustment mechanism for either the aforementioned valve or other valve for the draining of body fluids and a valve containing such adjustment mechanism by which the valve may be non-invasively adjusted trancutaneously from outside of the patient's body. In a valve and adjustment mechanism incorporating the principles of the present invention, a wide range of adjustment of the pressures or pressure differentials at which the valve will drain the fluid is possible. Such adjustment can be performed virtually continuously to enable fine tuning of the valve. A valve and adjustment mechanism incorporating the principles of the present invention is simple in manufacture and operation, and is extremely reliable. A valve and adjustment mechanism incorporating the principles of the present invention may be adjusted with a minimum of torque and minimal possibility of jamming and, once adjusted, the valve and mechanism may be reliably locked in its desired adjustment position.
In one principal aspect of the present invention, adjustment means for a valve which includes a passage in the valve for the flow of fluid through the valve and flow-restricting means for restricting the flow through the passage comprises an elongate rotatable magnet in the valve. The magnet is mounted to the flow restricting means to rotate same to adjust the pressure at which the fluid will flow through the flow restricting means when the magnet is rotated. The magnet is also movable between a first active position and a second inactive position in which the magnet is capable of rotating the flow restricting means to adjust the pressure when the magnet is in its first active position and is incapable of performing such adjustment when in its second inactive position.
In still another principal aspect of the present invention, the aforementioned magnet is longitudinally movable between the first active position and the second inactive position.
In still another principal aspect of the present invention, the aforementioned adjustment means includes valve seat means and valve closure means having screw means and the screw means is engaged by the magnet to rotate the screw means to adjust the force by which the valve closure means engages the valve seat means.
In still another principal aspect of the present invention, the adjustment means includes locking means for locking the magnet against rotation when the magnet is in its second inactive position.
In still another principal aspect of the present invention, the last mentioned locking means may include, either alternatively or in combination, magnetic means which attracts and holds the magnet when the magnet is in its second inactive position and/or detent means on the valve casing and magnet which engage each other.
In still another principal aspect of the present invention, the adjustment means includes pivot means on the valve casing and magnet which is operable when the magnet is in its first active position to cause the magnet to rotate about an axis defined by the pivot means.
In still another principal aspect of the present invention, the aforementioned valve and adjustment means therefor may be a valve for draining cerebrospinal fluid.
In still another principal aspect of the present invention, a valve for the passage of body fluids from one location in the body to another location and the regulation of the pressure of such fluids includes movable means having first and second surfaces of substantial area thereon. First coupling means communicates the area of the first surface with the fluid from the one location and a second coupling communicates the area of the second surface with the other location. Valve seat means on the movable means is movable therewith and includes a passage for the flow of fluid from the first to the second surfaces. Valve closure means is positioned on the side of the movable means adjacent the first surface. The valve closure means is engaged by the movable seat means to close the passage in response to a first lower pressure differential of the fluid acting on the first and second surfaces, and the movable means and its valve seat means are movable away from the valve closure means to open the passage in response to a second higher pressure differential of the fluid acting on the first and second surfaces. Adjustment means includes magnetically rotatable means for selectively rotating one of the valve seat means and valve closure means to adjust the force by which these means engage each other.
In still another principal aspect of the present invention, the aforementioned movable means is a flexible diaphragm.
In still another principal aspect of the present invention, the valve closure means includes mounting means for stationarily mounting the valve closure means such that the valve seat means moves relative to the valve closure means and the adjustment means includes magnetic means coupled to the mounting means for rotating the mounting means.
In still another principal aspect of the present invention, the adjustment means comprises a wrench which includes an elongate rotatable magnet. At least one projection extends from the magnet for engaging one of the valve seat means and valve closure means to rotate same when the magnet is rotated.
In still another principal aspect of the present invention, the adjustment means in the last mentioned valve includes screw means on the valve closure means which is engaged by the wrench to rotate the screw means and valve closure means to adjust the force by which the valve closure means engages the valve seat means.
In still another principal aspect of the present invention, the aforementioned wrench is also longitudinally movable between a first active position and a second inactive position and the wrench is capable of performing the adjustment when in its first active position and is incapable of performing the adjustment when in its second inactive position.
In still another principal aspect of the present invention, the last mentioned adjustment means includes locking means for locking the wrench against rotation when the wrench is in its second inactive position.
In still another principal aspect of the present invention, the last mentioned locking means may include, either alternatively or in combination, magnetic means which attracts and holds the magnet when the wrench is in its second inactive position and/or detent means on a stationary portion of the casing and the wrench which engage each other.
In still another principal aspect of the present invention, the valve may include a stationary casing and pivot means on the casing and aforementioned wrench which is operable, when the wrench is in its first active position, to cause the wrench to rotate about an axis defined by the pivot means.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.